It seems like Vernet answered a question that no one asked. This is not one of their better ideas. I use a LOT of Vernet equipment in my show. They make some great products that are good ideas, but this is not one of them.

Think of combining a TT with a p_ll and you'll get the idea of what's going on here. So, the TT is definitely not invisible, and you will need to wear a jacket to make the trick work.

Just buy one of their quality Thumbtips and a video that shows how to use it, and no one will ever see it.